KR20230160292A - Hot melt adhesive compositions and laminates - Google Patents

Abstract

A hot melt adhesive composition containing acid-modified polyolefin and copolyester and satisfying the following (1) to (5). (1) The copolyester contains a dicarboxylic acid component and a glycol component, and the melting point (T1) obtained by differential scanning calorimetry (DSC) is in the range of 80 to 150 ° C. (2) DSC of acid-modified polyolefin The melting point (T2) obtained is in the range of 60 to 150°C (3) |T1-T2|≤40°C (4) The acid value of the acid-modified polyolefin is AV (eq/ton), and the hydroxyl value of the copolyester is OHV. (eq/ton), 0.5≤AV/OHV≤4.5 (5) When the total of acid-modified polyolefin and copolyester is 100% by mass, 5 to 40% by mass of acid-modified polyolefin is contained, and the copolymerization It contains 60 to 95% by mass of polyester, and when the total of the entire hot melt adhesive composition is 100% by mass, the total amount of acid-modified polyolefin and copolyester is 70% by mass or more.

Description

Hot melt adhesive compositions and laminates

The present invention relates to a hot melt adhesive composition and a laminate bonded with the hot melt adhesive composition.

Olefin resins such as polypropylene (PP) and propylene/α-olefin copolymers are inexpensive, lightweight, and have excellent strength, chemical resistance, and hydrolysis resistance, so they are widely used in various fields, including automobiles and home appliances. In particular, in recent years, there has been a strong demand for weight reduction in order to improve the fuel efficiency of automobiles, and it has been widely considered as a replacement for metal. However, since these olefin resins do not have polarity, it has been difficult to obtain good adhesion to their molded products or films. In order to improve this defect, various methods have been attempted to oxidize the surface of the olefin resin using chemical treatment with chemicals, corona discharge treatment, plasma treatment, flame treatment, etc. However, these methods not only require special equipment, but also cannot be said to be sufficient in improving adhesion or paintability.

Chlorinated polyolefins and acid-modified polyolefins have been developed as a device for imparting good paintability and adhesiveness to olefin resins by relatively simple methods. Since polyolefins are usually insoluble in solvents, designs have been made to reduce crystallinity and increase solubility by chlorination or copolymerization with α-olefins. Additionally, since crystallinity decreases even when acid modification is performed, resins with relatively good solubility have been obtained through acid modification. However, these resins have low compatibility with polar resins, and there is a problem in that good adhesion with highly polar resins such as polyvinyl chloride (PVC) or polyethylene terephthalate (PET) cannot be obtained.

Therefore, epoxy-based adhesives and urethane-based adhesives are used to bond olefin resins and ester resins. They exhibit excellent mechanical properties because they form three-dimensional crosslinks through the reaction of the resin and the curing agent (e.g., patent document 1). Additionally, a resin composition containing polyester and modified polyolefin is disclosed (for example, patent document 2).

Patent Document 1: Japanese Patent Publication No. 4-323292 Patent Document 2: Japanese Patent Publication No. 5-86239

However, the adhesive of Patent Document 1 is generally a two-component type containing a resin and a curing agent, and requires accurate weighing and mixing before use, and poor workability is cited as a problem. In addition, since it gelates in a short time after mixing, the pot life is short, on the order of tens of minutes to several hours, making it unsuitable for automatic application using a dispenser, etc., and there is a problem that the excess needs to be discarded. Additionally, because hardening requires a time of tens of minutes to several hours, low productivity is also a problem. In addition, since the resin composition of Patent Document 2 uses polyester having an amide bond, the melt viscosity increases significantly due to hydrogen bonding between the amide bonds of the polyester or hydrogen bonding between the amide bond and the modified polyolefin. , there is a problem that the adhesiveness is also reduced.

The object of the present invention is to improve the above-mentioned workability and productivity, and to provide good adhesion to olefin substrates such as polypropylene and also to high polarity substrates such as PVC and PET. , and also to provide a hot melt adhesive composition with excellent mechanical properties.

In order to achieve the above object, the present inventors conducted intensive studies and came up with the following invention. That is, the present invention relates to the hot melt adhesive composition shown below and a laminate using the hot melt adhesive composition.

A hot melt adhesive composition containing acid-modified polyolefin and copolyester and satisfying the following (1) to (5).

(1) The copolyester contains a dicarboxylic acid component and a glycol component, and the melting point (T1) obtained by differential scanning calorimetry (DSC) is in the range of 80 to 150 ° C.

(2) The melting point (T2) of the acid-modified polyolefin obtained by differential scanning calorimetry (DSC) is in the range of 60 to 150°C.

(3) |T1-T2|≤40℃

(4) When the acid value of the acid-modified polyolefin is AV (eq/ton) and the hydroxyl value of the copolymerized polyester is OHV (eq/ton), 0.5≤AV/OHV≤4.5.

(5) When the total of acid-modified polyolefin and copolyester is 100% by mass, it contains 5 to 40% by mass of acid-modified polyolefin, 60 to 95% by mass of copolyester, and the entire hot melt adhesive composition. When the sum of is 100% by mass, the total amount of acid-modified polyolefin and copolyester is 70% by mass or more.

It is preferable that the acid-modified polyolefin resin is maleic anhydride-modified polyolefin.

Moreover, it is preferable that the polycarboxylic acid component of the copolymerized polyester contains both aromatic dicarboxylic acid and aliphatic dicarboxylic acid, and that the alkylene glycol component is saturated aliphatic glycol.

A laminate of a polyvinyl chloride substrate and a polyolefin substrate bonded by the hot melt adhesive composition described above.

The hot melt adhesive composition of the present invention has both a non-polar component and a polar component by using a specific amount of a specific copolyester and an acid-modified polyolefin, so it can be used as an olefin substrate such as polypropylene and a polar substrate such as PVC or PET. It has good adhesion between different types of substrates.

Hereinafter, the present invention will be described in detail. It is essential that the hot melt adhesive composition of the present invention contains acid-modified polyolefin and copolyester and satisfies the following (1) to (4).

<Hot melt adhesive composition satisfying (1)>

(1) is explained. The copolyester used in the hot melt adhesive composition of the present invention contains a dicarboxylic acid component and a glycol component, and has a melting point (T1) in the range of 80 to 150 ° C. obtained by differential scanning calorimetry (DSC). Preferably it is 90 to 120°C, more preferably 95 to 115°C. When T1 is 80°C or higher, the heat resistance of the hot melt adhesive composition tends to become good. When T1 exceeds 150°C, a greater amount of heat needs to be applied when melting the hot melt adhesive composition, which has adverse effects both economically and environmentally.

<Hot melt adhesive composition satisfying (2)>

(2) is explained. The melting point (T2) of the acid-modified polyolefin used in the present invention obtained by differential scanning calorimetry (DSC) is in the range of 60 to 150°C. Preferably it is 65 to 125°C, more preferably 70 to 110°C. When T2 is 60°C or lower, the heat resistance of the hot melt adhesive composition decreases. When T2 is 150°C or higher, a greater amount of heat needs to be applied when melting the hot melt adhesive composition, which has adverse effects both economically and environmentally.

<Hot melt adhesive composition satisfying (3)>

(3) is explained. The hot melt adhesive composition used in the present invention is |T1-T2|≤40(℃). Preferably |T1-T2|≤30(℃), more preferably |T1-T2|≤20(℃). When |T1-T2| exceeds 40°C, when adhesion by heating is performed, only the low-melting point component melts first, and the adhesive strength with the polar substrate may decrease.

<Hot melt adhesive composition satisfying (4)>

(4) is explained. When the acid value of the acid-modified polyolefin constituting the hot melt adhesive composition of the present invention is AV (eq/ton), and the hydroxyl value of the copolyester is OHV (eq/ton), 0.5≤AV/OHV≤4.5. Preferably, 0.8≤AV/OHV≤3.5, more preferably 1.0≤AV/OHV≤3.0. When 0.5>AV/OHV, the ratio of hydroxyl groups in the polyester to the acid in the acid-modified polyolefin decreases, thereby weakening the hydrogen bond and lowering the melt viscosity. If the melt viscosity is lowered, shear force is not applied when the hot melt adhesive composition is melt-kneaded, the acid-modified polyolefin and polyester are not dispersed in a good state, and the adhesion to the substrate is reduced. When AV/OHV≤4.5, the melt viscosity of the hot melt adhesive composition does not become too high, and wettability to the substrate becomes good, and especially adhesion to polyvinyl chloride (PVC) becomes good.

<Hot melt adhesive composition satisfying (5)>

(5) is explained. The hot melt adhesive composition of the present invention contains 5 to 40% by mass of acid-modified polyolefin and 60 to 95% by mass of copolyester when the total of acid-modified polyolefin and copolyester is 100% by mass. Preferably, it contains 20 to 40% by mass of acid-modified polyolefin and 60 to 80% by mass of copolyester. More preferably, it contains 25 to 35% by mass of acid-modified polyolefin and 65 to 75% by mass of copolyester. In compositions outside the above range, when adhering to different types of substrates, the balance of polarity is biased, so good adhesion to both substrates cannot be obtained. In addition, the composition of the acid-modified polyolefin and the copolyester must satisfy the above range, and when the total of the entire hot melt adhesive composition is 100% by mass, the total amount of the acid-modified polyolefin and the copolyester must be 70% by mass or more. there is. Preferably it is 80 mass% or more, more preferably 90 mass% or more.

<Acid modified polyolefin>

Examples of the pyic acid-modified polyolefin that forms the basis of the acid-modified polyolefin used in the present invention include polyethylene, polypropylene, ethylene-propylene copolymer, propylene-butene copolymer, and ethylene-propylene-butene copolymer. . Among them, at least one selected from the group consisting of polypropylene, ethylene-propylene copolymer, and ethylene-propylene-butene copolymer (hereinafter also referred to as propylene-based polymer) has heat resistance and compatibility with copolymerized polyester. It is desirable in The propylene component in the propylene polymer is preferably 50 mol% or more, and more preferably 70 mol% or more. Additionally, as the pyic acid-modified polyolefin, a copolymerization of an unsaturated acid such as (meth)acrylic acid ester or (meth)acrylic acid, an alkyl ester of an unsaturated acid, vinyl acetate, ethylene, propylene, and α-olefin can be used.

The acid-modified polyolefin used in the present invention is obtained by graft polymerizing (hereinafter also referred to as acid-modifying) at least one type selected from the group consisting of an unsaturated carboxylic acid having 3 to 10 carbon atoms, its acid anhydride, and its ester. desirable. The weight of the graft chain (hereinafter also referred to as the acid-modified amount) relative to the entire acid-modified polyolefin is preferably 0.5 to 10% by mass. More preferably, it is 0.7 to 3% by mass. If the weight fraction of the graft chain is outside the above range, the adhesion to the polyolefin substrate may decrease.

Examples of unsaturated carboxylic acids having 3 to 10 carbon atoms, their acid anhydrides, and esters thereof include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid, maleic anhydride, and itaconic anhydride. Examples include acid anhydrides of unsaturated carboxylic acids such as conic acid and citraconic anhydride, and alkyl esters of unsaturated carboxylic acids such as methyl acrylate, methyl methacrylate, and dimethyl maleate. Among these, maleic acid, itaconic acid and their acid anhydrides are preferable.

Graft polymerization when producing the acid-modified polyolefin in the present invention can be performed by a known method, and the method is not particularly limited. For example, this can be done by adding an organic peroxide to a molten mixture of the polyolefin and the unsaturated carboxylic acid component. Alternatively, it can be performed by adding an organic peroxide to a mixture solution of the polyolefin and the unsaturated carboxylic acid component dissolved in a solvent such as toluene or xylene. When carrying out graft polymerization, it is desirable to avoid mixing of air and oxygen, and it is desirable to carry out the graft polymerization in an inert gas atmosphere such as nitrogen gas. Examples of the organic peroxide include acetylcyclohexylsulfonyl peroxide, benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, lauroyl peroxide, etc., and one or two types of these may be used. The above can be used together.

The melt viscosity of the acid-modified polyolefin at 190°C is preferably 1,000 to 20,000 mPa·s, more preferably 2,000 to 15,000 mPa·s, and still more preferably 3,000 to 13,000 mPa·s. When the melt viscosity is 1,000 mPa·s or less, the cohesion decreases, so the adhesive strength to the substrate decreases, and when the melt viscosity is 20,000 mPa·s or more, the adhesion to the substrate decreases. Additionally, the melt viscosity of the copolyester at 190°C is preferably 220,000 mPa·s or less, and more preferably 200,000 mPa·s or less. Above 220,000 mPa·s, the adhesion to the substrate decreases.

The melting point T1 of the acid-modified polyolefin is preferably 60°C or higher, more preferably 65°C or higher, and even more preferably 70°C or higher. Additionally, it is preferably 150°C or lower, more preferably 140°C or lower, and even more preferably 130°C or lower. If the melting point of the acid-modified polyolefin is less than 60°C, there is a risk that the adhesiveness will be significantly reduced due to an increase in temperature in the usage environment, and if it exceeds 150°C, there is a risk that the olefin substrate may melt during adhesion. Additionally, when the melting point of the copolyester is T2, it is preferable that |T1-T2|≤40 (°C). When |T1-T2| exceeds 40°C, when adhesion by heating is performed, only the low-melting point component melts first, and the adhesive strength with the polar substrate may decrease.

The weight average molecular weight (Mw) of the acid-modified polyolefin is preferably 30,000 to 120,000, more preferably 40,000 to 110,000, and still more preferably 50,000 to 100,000. Additionally, the number average molecular weight (Mn) is preferably 10,000 to 70,000, more preferably 15,000 to 60,000, and still more preferably 20,000 to 55,000. Additionally, the molecular weight distribution (Mw/Mn) is preferably 3 or less, and more preferably 2.8 or less. By using the acid-modified polyolefin in the above range, compatibility with copolyester can be improved, and the adhesion of the hot melt adhesive composition can be improved.

The AV of the acid-modified polyolefin is preferably 50 to 500, more preferably 100 to 400, and still more preferably 150 to 300. At 50>AV, the adhesion of the acid-modified polyolefin to the polyolefin substrate is low, so the adhesive strength decreases. At 500<AV, the cohesive force of the acid-modified polyolefin decreases and the adhesive force decreases.

<Copolymerized polyester>

The copolyester used in the present invention is obtained, for example, by dehydration condensation or dealcohol condensation of a dicarboxylic acid component such as dicarboxylic acid or its anhydride or alkyl ester and a glycol component.

As compounds forming the dicarboxylic acid component, aromatic dibasic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 1,2-naphthalenedicarboxylic acid, and 1,6-naphthalenedicarboxylic acid, or succinic acid, Dipic acid, azelaic acid, sebacic acid, dodecanoic acid, dimer acid, hydrogenated dimer acid, dodecenyl succinic anhydride, fumaric acid, dodecanedioic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclo Hexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, etc., aliphatic dicarboxylic acids such as maleic acid, maleic anhydride, itaconic acid, and citraconic acid. Examples include boxylic acids and alicyclic dicarboxylic acids.

When the total dicarboxylic acid component is 100 mol%, it is preferable that the aromatic dicarboxylic acid contains 40 mol% or more, more preferably 45 mol% or more, and even more preferably 50 mol% or more. The upper limit is not particularly limited and may be 100 mol%, but is preferably 95 mol% or less, and more preferably 90 mol% or less. The content of aliphatic dicarboxylic acid and alicyclic dicarboxylic acid is preferably 60 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less. If the aromatic dicarboxylic acid is too little or the aliphatic dicarboxylic acid and cycloaliphatic dicarboxylic acid are too much, the adhesiveness and heat resistance of the hot melt adhesive composition may decrease.

The OHV of the copolyester is preferably 20 to 200. More preferably, it is 30 to 170, and even more preferably, it is 50 to 150. At 30>OHV, the interaction with the acid-modified polyolefin decreases, resulting in poor dispersion when melt-kneaded. At 150<OHV, when the adhesive layer is bonded, the adhesion to the polyolefin substrate decreases.

As other glycol components, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3- Butylene glycol, 1,4-butylene glycol, 2-methyl-1,3-propylene glycol, neopentyl glycol, 1,6-hexamethylene glycol, 3-methyl-1,5-pentanediol, 2,2, 4-trimethyl-1,3-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2,2-dimethyl-3-hydroxypropyl-2' ,2'-dimethyl-3'-hydroxypropanate, 2-(n-butyl)-2-ethyl-1,3-propanediol, 3-ethyl-1,5-pentanediol, 3-propyl-1 , Aliphatic diols such as 5-pentanediol, 2,2-diethyl-1,3-propanediol, 3-octyl-1,5-pentanediol, 1,3-bis(hydroxymethyl)cyclohexane, 1 ,4-bis(hydroxymethyl)cyclohexane, 1,4-bis(hydroxyethyl)cyclohexane, 1,4-bis(hydroxypropyl)cyclohexane, 1,4-bis(hydroxymethoxy)cyclo Hexane, 1,4-bis(hydroxyethoxy)cyclohexane, 2,2-bis(4-hydroxymethoxycyclohexyl)propane, 2,2-bis(4-hydroxyethoxycyclohexyl)propane, Bis(4-hydroxycyclohexyl)methane, 2,2-bis(4-hydroxycyclohexyl)propane, 3(4),8(9)-tricyclo[5.2.1.02,6]decanedimethanol, etc. Examples include alicyclic glycols, aromatic glycols such as ethylene oxide adducts and propylene oxide adducts of bisphenol A, polyethylene glycol, polypropylene glycol, and polytrimethylene glycol. These can be used one type or two or more types together.

In addition, the copolyester used in the present invention can be copolymerized by substituting part of the dicarboxylic acid component with a trifunctional or higher carboxylic acid, or by substituting a portion of the glycol component with a trifunctional or higher polyol. Examples of these trifunctional or higher-functional compounds include trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, biphenyl tetracarboxylic acid, ethylene glycol bis(anhydrotrimellitate), glycerol tris(anhydrotrimellitate), etc. polyhydric carboxylic acids and their anhydrides, and polyfunctional glycols such as trimethylolpropane, pentaerythritol, glycerin, and polyglycerol.

In addition, the copolymerization polyester used in the present invention can be copolymerized or post-additioned with glycolic acid, lactones, lactides, or (poly)carbonates, or post-adducted with an acid anhydride, or copolymerized with glycolic acid.

It is preferable that the copolyester used in the present invention does not contain an amide bond in the main chain. The amount of amide bonds in the main chain of the copolyester is preferably less than 5 × 10 ^-4 mol per 100 g of the copolyester. More preferably, it is 1×10 ^-4 mol, and even more preferably, it is 1×10 ^-5 mol or less. When 5 × 10 ^-4 mol or more of the amide bond is contained, the melt viscosity significantly increases due to hydrogen bonding between amide bonds in the copolyester or hydrogen bonding between the amide bond and the acid-modified portion of the acid-modified polyolefin, resulting in adhesion. There is a risk that performance will deteriorate.

The melt viscosity of the copolyester at 190°C is preferably 220,000 mPa·s or less, and more preferably 200,000 mPa·s or less. Below 220,000 mPa·s, adhesion to the substrate is good.

The melting point T2 of the copolyester is preferably 80°C or higher, more preferably 85°C or higher, and even more preferably 90°C or higher. Additionally, it is preferably 150°C or lower, more preferably 130°C or lower, and even more preferably 120°C or lower. If T2 is less than 80°C, there is a risk that the adhesiveness will be significantly reduced due to an increase in the temperature of the usage environment, and if it exceeds 150°C, there is a risk that the olefin substrate may melt during adhesion.

The copolyester may be a crystalline copolyester or an amorphous copolyester, but is preferably a crystalline copolyester. If it is a crystalline copolyester, an improvement in adhesive strength can be expected due to an improvement in the strength of the resin due to crystallization.

Additionally, it is preferable to add an antioxidant to the hot melt adhesive composition of the present invention. Preferred antioxidants include hindered phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, amine-based antioxidants, etc.; however, one or two or more types of these can be used in combination. In particular, combined use of hindered phenolic antioxidants and other antioxidants is effective. Additionally, it is desirable to add stabilizers such as heat-aging inhibitors, anti-freezing agents, antistatic agents, light stabilizers, and ultraviolet absorbers. In particular, it is preferable to use a phenol-based antioxidant containing a phosphorus atom in the molecule because it can efficiently capture radicals. Furthermore, a crystal nucleating agent, a flame retardant, etc. may be added.

As hindered phenolic antioxidants and stabilizers, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,1,3-tri(4-hydr) Roxy-2-methyl-5-t-butylphenyl)butane, 1,1-bis(3-t-butyl-6-methyl-4-hydroxyphenyl)butane, 3,5-bis(1,1-dimethyl) Ethyl)-4-hydroxy-benzenepropanoic acid, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 3-(1,1- Dimethylethyl)-4-hydroxy-5-methyl-benzenepropanoic acid, 3,9-bis[1,1-dimethyl-2-[(3-t-butyl-4-hydroxy-5-methylphenyl)propylene oneyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, 1,3,5-trimethyl-2,4,6-tris(3',5'-di-t-butyl -4'-hydroxybenzyl)benzene, thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di -tert-butyl-4-hydroxyphenyl) propionate, N,N'-hexane-1,6 diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide), 3,3',3",5,5',5"-hexa-tert-butyl-a,a',a"-(mesitylene-2,4,6 triyl)tri-p-cresol, diethyl [[3,5-bis[1,1-dimethylethyl]-4-hydroxyphenyl]methyl]phosphate, 4,4'-butylidenebis(3-methyl-6-t-butylphenol), 2' ,3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide, 3,9-bis[2-{3-(3-tert- butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5·5]undecane, etc.

As phosphorus-based antioxidants and stabilizers, 3,9-bis(p-nonylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, 3,9-bis( Octadecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, tri(mononylphenyl)phosphite, triphenoxyphosphine, isodecylphosphite, iso Decylphenylphosphite, diphenyl 2-ethylhexylphosphite, dinonylphenylbis(nonylphenyl)esterphosphoric acid, 1,1,3-tris(2-methyl-4-ditridecylphosphite-5-t -Butylphenyl)butane, tris(2,4-di-tert-butylphenyl)phosphite, pentaerythritolbis(2,4-di-tert-butylphenylphosphite), 2,2'-methylenebis(4) ,6-di-tert-butylphenyl) 2-ethylhexylphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis[2,4-bis[1,1 -dimethylethyl]-6-methylphenyl]ethyl ester phosphorous acid, 6-[3-(3-tert-butyl-4-hydroxy-5-methyl)propoxy]-2,4,8,10-tetra-tert- Butyldibenz[d,f][1,3,2]-dioxaphosphepine, tetrakis(2,4-di-tert-butylphenyl)[1,1-biphenyl]-4,4'-di Examples include bisphosphonite and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite.

As sulfur-based antioxidants and stabilizers, 4,4'-thiobis[2-tert-butyl-5-methylphenol]bis[3-(dodecylthio)propionate], thiobis[2-(1,1- Dimethylethyl)-5-methyl-4,1-phenylene]bis[3-(tetradecylthio)-propionate], pentaerythritol tetrakis(3-n-dodecylthiopropionate), bis( Tridecyl)thiodipropionate, didodecyl-3,3'-thiodipropionate, dioctadecyl-3,3'-thiodipropionate, 4,6-bis(octylthiomethyl)-o -Cresol, 4,4-thiobis(3-methyl-6-tert-butylphenol), etc. can be mentioned.

As an amine-based antioxidant or stabilizer, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine or 2',3-bis[[3-[3,5-di-tert-butyl-4-hydroxy phenyl]propionyl]]propionohydrazide, N,N'-di-2 naphthyl-p-phenylenediamine, N-phenyl-N'-4,4'-thiobis(2-t-butyl-5 -methylphenol), 2,2-bis[3-(dodecylthio)propanoyloxymethyl]-1,3-propanediolbis[3-(dodecylthio)propionate], etc.

The amount of antioxidant added is preferably 0.1% by mass or more and 5% by mass or less with respect to the entire hot melt adhesive composition. If it is less than 0.1% by mass, the effect of preventing thermal deterioration may be insufficient. If it exceeds 5% by mass, it may adversely affect adhesiveness, etc.

The hot melt adhesive composition of the present invention may contain other resins such as epoxy resin, polyamide resin, polyolefin resin, polycarbonate resin, acrylic resin, ethylene vinyl acetate resin, and phenol resin, to the extent that the performance of the present invention is not impaired. In some cases, adhesiveness, flexibility, durability, etc. can be improved. The mixing amount of other resins is preferably less than 5% by mass of the entire hot melt adhesive composition. Additionally, curing agents such as isocyanate compounds and melamine, fillers such as talc and mica, pigments such as carbon black and titanium oxide, and flame retardants such as antimony trioxide and brominated polystyrene may be added.

A tackifier such as rosin or terpene may be added to the hot melt adhesive composition of the present invention to improve adhesion. The mixing amount is preferably less than 5% by mass of the entire hot melt adhesive composition.

The method of producing the hot melt adhesive composition of the present invention is not particularly limited and includes, for example, a method of melt-kneading with an extruder such as a single-screw extruder or a twin-screw extruder, a method of directly obtaining a molded product by blending pellets and melt-kneading with a molding machine, or copolymerization. Examples include a method of adding and mixing acid-modified polyolefin during polymerization of polyester, and a method of blending the two in a solution, but a method using a twin-screw extruder capable of applying high shear stress is particularly preferable. When using a twin-screw extruder, it is preferable to melt-knead at a temperature higher than the melting point of the acid-modified polyolefin or copolyester used, and specifically, it is preferable to melt-knead at 150 to 300°C.

<Description>

As the polar substrate used in the present invention, substrates such as polyethylene terephthalate (PET) and polyvinyl chloride (PVC) can be used. Additionally, the polyolefin substrate is not particularly limited, and substrates such as polyethylene (PE) and polypropylene (PP) can be used. Among them, a combination of PVC and PP is preferable.

<Laminate>

The laminate of the present invention is a three-layer laminate (polar substrate/hot melt adhesive composition layer/polyolefin substrate) in which a polar substrate and a polyolefin substrate are laminated with a hot melt adhesive composition. A laminate can be produced, for example, by laminating or applying a hot melt adhesive composition to a polyester base (or polyolefin base), sandwiching the composition with a polyolefin base (or polyester base), and thermocompression bonding. The thickness of the hot melt adhesive composition layer in the laminate is preferably 5 to 200 μm, more preferably 10 to 100 μm, and still more preferably 15 to 50 μm. If the thickness is too thin, sufficient adhesive performance may not be obtained, and if the thickness is too thick, productivity may decrease.

Example

Hereinafter, the present invention will be described in more detail through examples. However, the present invention is not limited to the examples. In addition, in examples and comparative examples, those simply written as parts represent parts by mass, and those written as % represent mass%.

<<Evaluation method of resin and hot melt adhesive composition>>

<Composition cost>

A sample (copolymerized polyester or acid-modified polyolefin) was dissolved in chloroform-d, and 1H-NMR analysis was performed using a nuclear magnetic resonance spectrometer (NMR) Gemini-200 manufactured by Varian Corporation to determine the result.

<Acid value (AV) of acid-modified polyolefin>

The acid value (eq/ton) of the acid-modified polyolefin in the present invention is determined by measuring the stretching peak of the carbonyl (C=O) bond of maleic anhydride using FT-IR (FT-IR8200PC manufactured by Shimadzu Seisakusho). The absorbance (I) of (1780 cm ^-1 ), the absorbance (II) of the isotactic peak (840 cm ^-1 ), and the factor (f) obtained from the calibration curve prepared with a chloroform solution of maleic anhydride (Tokyo Kasei) ), the value calculated by the formula below was expressed as the equivalent weight (eq/ton) in 1 ton of resin.

Acid value = [Absorbance (I) / Absorbance (II) × (f) / Molecular weight of maleic anhydride × 2 × 104]

Molecular weight of maleic anhydride: 98.06

<Hydroxyl value (OHV) of copolymerized polyester>

The hydroxyl value of the copolyester in the present invention was determined as follows. Copolymerized polyester: 50 g was dissolved in 120 g of heated chloroform, 4,4'-diphenylmethane diisocyanate: 70 g was added, and reacted at 70°C for 2 hours. Next, the concentration of the remaining isocyanate groups in the reaction solution was quantified by titration, and the hydroxyl value (eq/ton) was determined.

<Mel Viscosity>

Using a flow tester (CFT-500C type) manufactured by Shimadzu Seisakusho, a resin sample (copolymerized polyester or acid-modified polyolefin) dried to a moisture content of 0.1% or less was filled into a cylinder in the center of a heating element set at 190°C. After 3 minutes of charging, pressure (4.9 MPa) is applied to the sample through the plunger to extrude the molten sample from the die (hole diameter: 0.5 mm, thickness: 20 mm) at the bottom of the cylinder, and the drop distance and drop of the plunger are The time was recorded and the melt viscosity (mPa·s) was calculated.

<Weight average molecular weight (Mw), number average molecular weight (Mn)>

Mw and Mn in the present invention are gel permeation chromatography Alliance e2695 (hereinafter also referred to as GPC) manufactured by Nippon Waters. Standard material: polystyrene resin, mobile phase: tetrahydrofuran, column: Shodex KF-806+ This value was measured using KF-803, column temperature: 40°C, flow rate: 1.0 ml/min, detector: photodiode array detector (wavelength: 254 nm = ultraviolet rays).

<Melting point>

Using a differential scanning calorimeter "DSC220 type" manufactured by Seiko Denshi Kogyo Co., Ltd., put 5 mg of the measurement sample (copolymerized polyester or acid-modified polyolefin) into an aluminum pan, press the lid to seal, and hold once at 250°C for 5 minutes. After the sample was completely melted, it was rapidly cooled with liquid nitrogen and then measured at a temperature increase rate of 20°C/min from -150°C to 250°C. From the obtained thermogram curve, the maximum endothermic peak of heat of fusion was taken as the melting point.

<Production of sheet-shaped sample of hot melt adhesive composition>

Using a tabletop test press SA-302 manufactured by Tester Sangyo Co., Ltd., a sheet-like sample of the hot melt adhesive composition with a thickness of 20 μm was molded at 160° C., holding pressure of 20 MPa, and holding pressure time of 10 seconds.

<Adhesion strength evaluation>

The sheet-shaped sample was sandwiched between a PVC film (BONLEX BE, 50 ㎛ thick) manufactured by Takyron-CI Co., Ltd. and a polypropylene plate (2.5 ㎜ thick) manufactured by Nippon Test Panel Co., Ltd. Using a heat seal tester IMC-0800, a sample for measuring adhesive strength was formed by holding at 140°C and holding pressure of 0.1 MPa for 120 seconds. The sample for measuring adhesive strength was cut to a width of 10 mm, the PVC film of the sample for measuring adhesive strength was placed on the upper chuck of a tensile tester manufactured by Shimazu Seisakusho Co., Ltd., and the polypropylene plate was placed on the lower chuck, at 23°C. The 180° peel adhesive strength was measured by pulling up and down at a tensile speed of 50 mm/min using an Autograph AGX-V in an environment of 60% Rh. Evaluation was conducted based on measured values and comprehensive evaluation.

(comprehensive evaluation)

○: The hot melt adhesive composition undergoes cohesive failure and the peel strength is 15 N/10 mm or more.

△: (1) the hot melt adhesive composition peels from the polypropylene plate or PVC film interface and the peel strength is 10 N/10 mm or more, or (2) the hot melt adhesive composition cohesively fails and the peel strength is 10 N/10 mm or more. It is in the range of 10 N/10 mm or more and less than 15 N/10 mm.

×: Peel strength is less than 10 N/10 mm.

<<Manufacturing Examples and Examples>>

Production example of acid-modified polyolefin (a)

100 parts by mass of crystalline polypropylene (polyolefin resin 1), 8 parts by mass of maleic anhydride, 2 parts by mass of dicumyl peroxide, and 150 parts by mass of toluene were placed in an autoclave equipped with a stirrer, and purified with nitrogen for 5 minutes after sealing. did. After that, the reaction was performed at 140°C for 5 hours while heating and stirring. After completion of the reaction, the reaction solution was poured into a large amount of methyl ethyl ketone to precipitate the resin. The precipitated resin was taken out, washed several times with methyl ethyl ketone, and then dried to obtain acid-modified polyolefin (a). Composition and properties are shown in Table 1.

Production examples of acid-modified polyolefins (b) to (f)

In the same manner as for the acid-modified polyolefin (a), acid-modified polyolefins (b) to (e) were obtained by changing the type of polyolefin resin to be modified. The composition and properties of each acid-modified polyolefin are shown in Table 1.

Polyolefin resin 1: propylene-butene (=70/30 (molar ratio)) copolymer (weight average molecular weight 230,000)

Polyolefin Resin 2: Propylene-butene (=90/10 (molar ratio)) copolymer (weight average molecular weight 180,000)

Polyolefin Resin 3: Propylene-ethylene-butene (=70/10/20 (molar ratio)) copolymer (weight average molecular weight 170,000)

Production example of copolyester (A)

In a reaction can equipped with a stirrer, thermometer, and outlet cooler, 30 parts by mass of terephthalic acid, 20 parts by mass of isophthalic acid, 50 parts by mass of adipic acid, 100 parts by mass of 1,4-butanediol, and 0.25 parts by mass of tetrabutyl titanate. was added, and an esterification reaction was performed at 170 to 220°C for 2 hours. After completion of the esterification reaction, 0.5 parts by mass of hindered phenolic antioxidant "Irganox (registered trademark) 1330" (manufactured by BASF Japan Co., Ltd.) was added, and the temperature was raised to 255°C, while the inside of the system was slowly reduced in pressure. Then, the temperature was adjusted to 665 Pa at 255°C over 60 minutes. Then, a polycondensation reaction was further performed at 133 Pa or less for 30 minutes to obtain polyester resin (A). The melting point of this polyester resin (A) was 110°C, and the melt viscosity at 190°C was 180,000 mPa·s.

Production example of copolymerized polyester (B) to (D)

In the same manner as for copolyester (A), copolyester resins (B) to (D) were obtained by changing the dicarboxylic acid component and glycol component. The characteristics of each resin are shown in Table 2.

TPA: Terephthalic acid

IPA: isophthalic acid

AA: adipic acid

EG: ethylene glycol

BD: 1,4-butanediol

PTMG1000: Polytetramethylene glycol (number average molecular weight 1000)

Example 1

Hot melt adhesive composition (1)

Adding 30 parts by mass of the acid-modified polyolefin (a) as the acid-modified polyolefin and 70 parts by mass of the co-polyester (A) as the co-polyester, melt-kneading at 190°C using a twin-screw extruder to produce a hot melt adhesive composition. (1) was obtained. As a result of measuring the adhesive strength using the method described above, it was 20 N/cm. The composition and properties are shown in Table 3.

Examples 2 to 9, Comparative Examples 1 to 8

Preparation examples 2 to 17 of hot melt adhesive composition

According to the combination of Tables 3 and 4, hot melt adhesive compositions 2 to 17 were obtained in the same manner as in Production Example 1. Adhesion strength was measured using the method described above. The composition and properties are shown in Tables 3 and 4.

Unmodified polyolefin: J-700GP (homopolypropylene manufactured by Prime Polymer Co., Ltd.)

Examples 1 to 9 satisfy the scope of the patent claims and have good adhesive strength. Comparative Example 1 is outside the scope of the present invention because it contains more than 95% by mass of copolyester, and the adhesion to the PP film is low. Comparative Example 2 is outside the scope of the present invention because it contains more than 50% by mass of acid-modified polyolefin, and the adhesion to the PVC film is low. Comparative Example 3 had an AV/OHV of 4.5 or more, which was outside the scope of the present invention and had low adhesion to PP and PVC films. Comparative Example 4 is |T1-T2|>40, and the adhesiveness is lowered because the dispersion of the adhesive layer becomes non-uniform. Since Comparative Example 5 does not contain acid-modified polyolefin, the adhesion to PP is low. Since Comparative Example 6 does not contain copolyester, the adhesion to PVC is low. In Comparative Example 7, unmodified polyolefin adhesive was used instead of acid-modified polyolefin, and the adhesiveness to the PP substrate was lowered. In Comparative Example 8, when the total amount of the entire hot melt adhesive composition is 100% by mass, the total amount of acid-modified polyolefin and copolyester is less than 70% by mass, so the adhesiveness is low.

Claims (4)

A hot melt adhesive composition containing acid-modified polyolefin and copolyester and satisfying the following (1) to (5).
(1) The copolyester contains a dicarboxylic acid component and a glycol component, and the melting point (T1) obtained by differential scanning calorimetry (DSC) is in the range of 80 to 150 ° C.
(2) The melting point (T2) of the acid-modified polyolefin obtained by differential scanning calorimetry (DSC) is in the range of 60 to 150°C.
(3) |T1-T2|≤40℃
(4) When the acid value of the acid-modified polyolefin is AV (eq/ton) and the hydroxyl value of the copolymerized polyester is OHV (eq/ton), 0.5≤AV/OHV≤4.5.
(5) When the total of the acid-modified polyolefin and copolyester is 100% by mass, the acid-modified polyolefin is contained from 5 to 40% by mass, and when the total of the entire hot melt adhesive composition is 100% by mass, the acid-modified adhesive composition contains 5 to 40% by mass. The total amount of polyolefin and copolyester is 70% by mass or more. The hot melt adhesive composition according to claim 1, wherein the acid-modified polyolefin resin is maleic anhydride-modified polyolefin. The hot melt adhesive composition according to claim 1 or 2, wherein the dicarboxylic acid component of the copolyester includes both aromatic dicarboxylic acid and aliphatic dicarboxylic acid, and the alkylene glycol component is saturated aliphatic glycol. . A laminate of a polyvinyl chloride substrate and a polyolefin substrate bonded by the hot melt adhesive composition according to any one of claims 1 to 3.